Which of the following Oracle features utilize the undo tablespace？（） 

A. list incarnation of database
B. report incarnation of database
C. list database incarnation
D. database incarnation list
E. report database incarnation

A. The datafiles have an ONLINE status.
B. The datafiles have an OFFLINE status.
C. The datafiles have an ONLINE status and are in hot backup mode prepared for an online backup.
D. The datafiles have an OFFLINE status and are in hot backup mode for an online backup.
E. The datafiles are in STANDBY mode.

A. The tablespace cannot be duplicated or restored to any point in time after the duplication. 
B. The tablespace cannot be duplicated or restored to the point in time before the duplication. 
C. The entire database cannot be restored after a TSPITR， so a backup is required.
D. You cannot bring the tablespace online until its been backed up.
E. There is no requirement to do so， as RMAN will back up the tablespace after the TSPITR.